The WLAN technology known as “Wi-Fi” can be used to offload traffic from wide-area cellular networks, such as 3GPP cellular networks. Interest in cooperation between WLANs and cellular networks is rapidly increasing, since virtually all smartphones support Wi-Fi. In some Wi-Fi descriptions, the term “Station” (STA) might be used instead of user equipment (UE). Accordingly, the terms UE, STA and terminal may be used interchangeably herein to describe wireless terminals that support both a cellular technology (such as Evolved Universal Terrestrial Radio Access, or E-UTRA) and WLAN.
In a Wi-Fi architecture, the wireless terminal (UE/STA) is connected on the user plane to the Wi-Fi Access Point (AP), which can be directly connected to the Internet. In the control plane, an Access point Controller (AC) may handle the management of the AP. One AC can handle the management of several APs. Security and authentication of users can be handled via an Authentication, Authorization and Accounting (AAA) entity, which may be a RADIUS server. Remote Administration Dial-In User Service (RADIUS) is the most widely used network protocol for providing a centralized AAA management (RFC 2865).
In working groups of the 3rd-Generation Partnership Project (3GPP), the functionality for sending data from a 3GPP network to a UE, via WLAN, is being standardized. The current architecture in 3GPP is shown in FIG. 1, where the WLAN Termination (WT) is a logical node connected to a 3GPP network (e.g., an eNB in E-UTRAN). The WLAN Termination is also connected to the WLAN.
However, when the UE has found and connected to an AP in WLAN, there is currently no mechanism for the eNodeB to find the UE on the WLAN side, or for the AP to find or know which WLAN Termination is connected to the eNodeB serving the UE.